The ability to duplicate and store the contents of a storage device is an important feature in many storage systems. In some storage systems, data is stored in parallel to safeguard against the failure of a single storage device or medium. Upon a failure of a first storage device or medium, the system retrieves a copy of the data contained in a second storage device or medium. The ability to duplicate and store the contents of the storage device also facilitates the creation of a fixed record of contents at the time of duplication. This feature allows users to recover a prior version of inadvertently edited or erased data.
In storage systems, space and processing costs are associated with copying and storing the contents of a storage device. For example, some storage devices cannot accept input/output (I/O) operations while its contents are being copied. Furthermore, the storage space used to keep the copy cannot be used for other storage needs.
In an effort to become more efficient and mitigate costs, storage systems and storage software products provide ways to make point-in-time copies of disk volumes, sometimes referred to as snapshots. In some storage systems, copies are quickly made without significantly disturbing applications using disk volumes. Further, copies can be made to share storage instead of copying all the disk volume data.
Storage systems that create snapshots, however, have limitations. Only a limited number of snapshots can be created under a single Logical Disk. Further, all snapshots created under the Logical Disk need to have a same RAID type. Further, current storage systems restrict users in creating snapclones or mirror clones if a snapshot already exists. If a user wants to make a mirror clone for a Logical Disk with existing snapshots, all existing snapshots have to be deleted before such operation.